Perl

I use Perl at work these days, mainly for Microsoft Office automation: the one whopping big file here, Excelnt.pm, gives you a Perl interface to Excel. I use it just about every day. All of the hundred or so subroutines come with examples in their introductory comments.

If you'd like a backup utility that's tuned for developers and small enough to tweak, take a look at backup.pl.

“Smithback is great at batch programs, but I don't think he's done any GUI programming....” Well, prove them wrong with ArgYouMeant.pm, you'll have a lovely dialog front-end on your batch program in just a few minutes.

For beginners (and the curious), minicgi.pl shows how to to do CGI with Perl (parses its arguments, gets and sets cookies, reads files, and retrieves results from other sites), without using a whole swack of extra modules.